1. Field of the Invention
This invention relates to an apparatus for automatically manufacturing plastic tubular elements having at least one end fitting, such elements being suitable for conveying liquids, in particular fuel for motor vehicles.
More particularly, this invention relates to an apparatus for automatically performing the operations of exactly cutting a given length of a tube of plastic material, preferably a thermoplastic material and in particular nylon, and of mounting on at least one of the cut tube ends, a fitting in the form of a rubber coupling or a metal insert. According to the foreseen uses, the mounting operation is carried out in such a manner as to ensure all necessary liquid sealing features under the stresses to which and tube and fitting will be subjected during the use of the motor vehicle.
2. Description of the Prior Art
Many methods and devices for performing operations of the type referred to are well known in the art, such devices usually being hand operated and including tube retaining jaws wherein a tube end is hand positioned and retained, means for positioning and retaining a fitting in a position co-axial with the tube end, and lever or cylinder-piston means for axially pushing the fitting within or onto the tube end. The tube or fitting end is open to respectively receive the fitting or tube by means of chamfers normally provided on the outer or inner edges of the fitting end.
The above known methods and devices are very expensive as they require manual operations and thereby provide very limited outputs. Further, these methods and devices carry out an insertion operation which is not reliable with reference to the hydraulic sealing of couplings, and often allow a mutual movement of the inserted means, so that separate sealing and retaining elements are required.